Hollow conductor



w. H. BASSETT HOLLOW CONDUCTOR Original Filed on. s, 1924 mvmfou' I mL/AM 17.545.553'71 h 45 its edges laterally projectin Retained Dec. n, 1928.

UNITED STATES our.

My l invention relates to hollow conductors whic are of relatively large diameter for a material so as to permit them to beused for 6 high voltage transmission without substantial corona loss or for otherpur 'oses requirand has for its object to produce a new and 10 improved hollow conductor of the required flexibility, high resistance to'mechanical i11 'ury liable to result from crushing stresses,

efliciency, and relatively low weight. My improved conductor may be -used bare or insulated as occasion re uires.

Conductors hereto ore made have been open to various objections. Thus, solid conductors when used for high voltage transmission are of such small diameter that the corona losses are so a transmission relative y ineificient, a disadvantage which numerous inventors' have attempted to overcome by making the conductors hollow and thus increasing the diameter of the conductors relatively to the cross-sectional area of. the conducting material.

, conductors in varlous ways, all which, however, have been found subject to certain disadvantages, which it is the purpose of my present invention to obviate.

A cable embodying my invention is shown in the accompanying drawings,

Fig. 1 shows a ortionof a cable partly in side elevation an partly broken away; Fig. 2 showsa transverse sectionoi' the same on the line 22 of Fi 4Q enlarged scale; and

Fi 4shows, on an enlarged scale, a modified orm of strip.

Referring more particularly to the draw- ;ings, 2 represents a twisted strip having at portions or 'fianges forming thickened e r es or heads in cross-section. The outer surfaces 66of these heads are curved so as to substantially conform to the inner surfaces .of ,wires or The central part strands cabled thereon. 8 of the body portion of the strip may be HOLLOW CONDUCTOR.

given cross-sectional area of the conducting ing maximum diameterand sur ace with reduced cross-section Of 00]1dl10tll'lg 111813611811,

ightensile strength, maximum. conducting eat as to render the It has been proposed to make such hollow in which 1' 1 Fig. 3 showsa portion 0% the strip on an conducting wires or 4-4 so as to make it substantially I-shaped. count of sleet and wind loads.

- section is fixed -rying capacity.

thickened so as to give the strip greaterten- PATENT OFFICE.

REISSUED 7 Original 1131 1,597,422, dated August 24, 1928, Seria1 No. 741,843, filed October 3, 1824. Application for reissue filed my 17, 1927. Serial No. 192,124.

sile strength as shown in Fig. 4. The twisted strip is twisted about-its lon 'tudinal axis, the preferable itch being a out one complete twist to our inches for a strip fiveeighths of an inch in width. A stri width whose body portion is .040 0? an inch thick and whose edges are .090 of an inch thick gives satisfactory results.

WILLIAM H. BASSETT, OF CHESHIRE, CONNECTICUT, ASSIGNOR TO THE AMERICAN BRASS COMPANY, OF WATERIBUBY, CONNECTICUT, A CORPORATION OF CONNECTI- I of such About-the twisted strip, wires or strands 10 are cabled and if desired another layer of v wires or strands 12, thus making up the completedcable as shown.. As shown in the drawings the wires or strands are round but obviously that form of wire or strand is not necessary to the embodiment of the invention.

In forming the cable the strip in untwisted form with its projecting flanges is first produced. 'It is then twistedas shown and then fed to a cabling machine where it is surrounded with one or more layers of conducting wires or strands thus producing the complete cable;

The thickened edges of the core are of especial importance in connection. with the manufacture of the cable. Where a flat strip is used, the strip being twisted often suddenly, changes from a spiral twist to a helical twist or curl which would continue fora foot or more before it could be stopped. In some cases in'working with the flat strip this has happened so often as to spoil the entire lot even for experimental purposes. Asingle of two, and maybe more, layers of strands and of different sizes' as in Fig. 2 has a special value in the production and in the use of the hollow style of cable. It is desirable to kee the external diameter of the cable smal on ac- The crossb the requisite current-cam There is a minimum'limit to the size of the wires, below which they are small and delicate and comparatively expen,

The use sive. But by making the conductor in two layers, the flexibility of the cable is imcan be made without defects inthe twist.

proved; and by using wires of different sizes in the two layers the combination of determined current-carrying capacity (or metal cross-section) and small outside diameter can be more closely approximated under the con- 'ditions of operation of conductor-laying ma.-

chines.

It is also important to have a comparatively wide bearing of the inner conducting wires on the core. A better cable to meet all these required conditions can be designed by using a plurality of layers, each layer made of strands which in turn consist of several wires and the wires or strands in the cable being spiralled in the same direction or m different directions.

The .flanges on the twisted strip constitute in effect a hollow spiral with a comparatively wide bearing face for the strands, the body portion constituting a comparatively narrow support extendlng across the 1nt er1or of the hollow spiral; and the invention includes various other constructions'than that specifically illustrated embodying this combination of hollow core and internal support.

Various other means than the flanges de-' scribed may be'used for stiffening the strip against longitudinal bending and for thus opposing its changing from the deslred spiral twist to a helical twist.

The strands or wires are of copper or bronze or similar metal of high conductivity such as is commonly used for conducting cables, and the core ispreferably of the same metal. The action of the edges of the core is therefore more important than would be the case in cables made of steel or similar hard metal.

Various other modifications than those described and suggested above may be made by those skilled in the art without departing from the invention as defined in the following claims.

What I claim is:

1. In a conducting cable comprising a series of strands cabled so as to form a tube, a core formed by a twisted strip having thickened conducting portions forming spiral surfaces engaged by said strands and supporting the same. I

2. In a conducting cable comprising a series of strands cabled so as toform a tube, a core formed by a twisted strip having a body portion and projecting flanges forming thickened edges thereon, said flanges providing thickened conducting port-ions and spiral surfaces engaged by said strands and supporting the same.

' 3. In aconducting cable comprising a series of strands cabled so as to form a tube, a core formed of a twisted strip having a thin body portion and projecting flanges upon its edges so as to have an I-shaped' cross-section, said flanges providing thickenedconducting ries of strands cabled so as to form a tube, a-

core formed by a twisted stri having a body portion and projecting anges forming thickened edges thereon, said flanges providing thickened conducting portions and spiral surfaces engaged by said strands and supporting the same,- said thickened conducting portions being about twice as thick as the adjacent body portion.

6. A conducting cable comprising a series of strands cabled so as to form a tube and a core including a twisted strip and means for stiflening said strip against longitudinal bending.

7. In a conducting cable comprising a series of strands cabled so as to form a tube, a

core formed by a twisted strip having a body portion and projecting flanges, said flanges forming a comparatively wide-faceds iral bearing for the cabled strands and said ody portion forming a comparatively narrow transverse support.

8. A flexible conductor for high voltage transmission which is hollow so as to have a comparatively large external surface with reduced metallic cross section, said conductor comprising strandscabled. so as to form a tube, comparatively wide-faced spiral bearin means for the internal surface of. said tube of cabled strands and comparatively narrow supporting means extending diametrically acrossthe space between opposite portions of said bearing means.

9. A flexible conductor for high voltage transmission which is hollow so as to have a comparatively large external surface with reduced metallic cross section, said conductor comprising strands cabled so as to forma tube and arrangedin a plurality of layers, the strands of the respective layers being of different sizes and being of metal of the same high conductivity, comparatively wide-faced spiral bearing means for the internal surface of said tube of cabled strands and compara tively narrow supporting means extending diametrically across the space between opposite portions of said bearing means.

In witness whereof, I have hereunto signed my 'name.

WILLIAM H. BASSET".. 

